Wide beam has always been a problem with trimarans, and the Float Connection Assemblies as described in U.S. Pat. No. 3,937,166 have solved this with a simple and effective method of retracting the stabilizing floats of a trimaran. The system is now widely used. However, the incorporation of these Float Connection Assemblies into a trimaran has proven to be difficult and time consuming.
Two construction methods have been used. The first is the standard wood frame, stringers and plywood planking construction method. With this method the Float Connection Assemblies require two carefully aligned bulkheads or frames either side of each connecting beam, to which pivot brackets are then attached. The position of these bulkheads is critical for accurate alignment of the connecting beams and the pivot assemblies. These bulkheads are of the usual wood frame type construction, and are used to support wood stringers, which in turn support plywood planking. In accordance with normal boat building practice these are built in during construction of the hull, and the pivot brackets must then be carefully attached and aligned. Accurately aligned mounting surfaces for the connecting beams must also be established between the bulkheads.
While this method has been reasonably successful, it requires a high level of building skill, a considerable amount of labor, and the two bulkheads take up interior room. The attachment of these bulkheads to the hull structure can be very important, and may limit the type of materials used to that as originally designed. Being a very labor intensive process, this method is not suitable for commercially produced trimarans and has only been used for amateur built trimarans.
The second construction method is the well established fiberglass production method of utilizing female molds in which the fiberglass hull is formed. With this construction a single fiberglass bulkhead at the center of each connecting beam is used in conjunction with very accurately aligned hull surfaces in this area, to provide correctly aligned mounting surfaces for the pivot brackets for the guide frame assemblies and a mounting surface or recess for the connecting beams. This method offers labor savings compared to the first method, but requires a considerable initial investment in very close tolerance tooling and is only suitable for production type molded fiberglass trimarans.
Both methods require integrating the Float Connection Assemblies, and their associated supports, piece by piece, very accurately, into the boat structure as it is built. This requires very detailed design, considerable building skills, very careful alignment, and a lot of labor.
Construction materials for the boat are also limited to what the designer has specified, due to the many varied stresses involved, and their resolution into the particular materials specified.
In all cases, the Float Connection Assemblies have been designed for a specific design, and are not suitable for use in other similar but different designs. A simple change in design shape of the hulls may require a complete redesign of the Float Connection Assemblies. Once a trimaran using this system is assembled, the Connecting Assemblies became part of that boat and can not be easily transferred to a similar size but different trimaran design. This is a particular disadvantage for racing trimarans, where a hull design is easily outdated, and a new hull design may be required. The ability to transfer the Float Connection Assemblies easily into a new central hull and/or stabilizing floats would offer great savings in time and expense.
It is, therefore, an object of this invention is to provide a construction method that will overcome the above and other disadvantages, and a method that will be easy and efficient to use. In particular, it is an object of this invention to provide a construction method in which the assembly of many different parts is not required. Other objects are to provide a construction method that eliminates accurate alignment of many different parts, and to provide a construction method that is independent of the materials used in the rest of the craft.